A strain of Sinclair miniature swine that are born with cutaneous malignant melanomas can cure their malignancy, and in the process they depigment their skin, hair and eyes. Melanocytes of the uveal tract, but not the melanin-containing cells of the neuroepithelial layers, are destroyed during ocular depigmentation. Uveitis, atrophy of the choriocapillaries, and photoreceptor degeneration accompany infiltration of the uvea by mononuclear cells and macrophages. We plan to study the natural course of the eye pathology by correlating the clinical, electrophysiologic, histologic, ultrastructural and immunologic phenomena. Serial slit lamp examinations will be used to determine the onset of uveitis and eyes will be enucleated at various stages of disease to evaluate the invading cell types. Immunoglobulin localization will be assessed by fluorescein -- peroxidase-labeled antibodies. Cytotoxicity of swine immunocompetent blood cells against the two populations of melanin-containing eye cells will be studied in vitro. We will search for uveal melanomas, and if found, use affected animals for breeding, study of the clinical course of tumor growth and eventually after enucleation, for histologic and tissue culture studies. Implantation of autologous melanoma cells into the suprachoroidea will be attempted if no naturally occurring uveal tumors are found.